Whelanite Ca5Cu2(OH)(2)CO3,Si6O17 center dot 4H(2)O-A vibrational spectroscopic study

作者：Frost Ray L^*; Xi Yunfei

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2012, 91: 319-323.

DOI：10.1016/j.saa.2012.02.003

• Whelanite
• Healing mineral
• Chrysocolla
• Silicate
• Raman spectroscopy
• Dioptase

Whelan ite Ca5Cu2(OH)(2)CO3,Si6O17 center dot 4H(2)O is a hydrated hydroxy mixed anion compound with both silicate and carbonate anions in the formula. The structural characterisation of the mineral whelanite remains incomplete. Whelanite is probably a neosilicate with Cu2+ in square planar coordination. Two Raman bands at 1070 and 1094 cm(-1) are assigned to the nu(1) symmetric stretching modes of the CO32- units. The observation of two symmetric stretching modes supports the concept of two non-equivalent CO32- units in the whelanite structure. The intense sharp Raman band at 1006 cm(-1) is assigned to the nu(1) (A(1g)) symmetric stretching vibration of the Si6O17 units. The splitting of the nu(3) vibrational mode offers support to the concept that the SiO4 tetrahedron in whelanite is strongly distorted. A very intense Raman band observed at 666 cm(-1) with a shoulder at 697 cm(-1) is assigned to the nu(4) vibrational modes. Intense Raman bands at 3534, 3556, 3550 and 3595 cm(-1) are assigned to the stretching vibrations of the OH units. Low intensity Raman bands at 2910, 3187 and 3453 cm(-1) are assigned to water stretching modes. Thus, vibrational spectroscopy has been used to characterise the molecular structure of whelanite. Whelanite is a mineral that could be conceived as a healing mineral.

• 出版日期2012-6